Facing issues while hardening the security of my Ubuntu droplet

I'm a newbie here and facing a couple issue with my droplet. Wanted to harden the security of my Ubuntu droplet but facing some issues. Googled a lot but can't see any solution of these problems. Any suggestion on how to fix these?

Disable source packet routing

Log Martians

net.ipv4.icmpignoreboguserrorrespons­es = 1

and reloaded the new rules by "sudo service procps start"

I get the following error after running "sysctl -p"

sysctl: cannot stat /proc/sys/net/ipv4/conf/default/acceptsourcerout­e: No such file or directory
sysctl: cannot stat /proc/sys/net/ipv6/conf/default/acceptsourcerout­e: No such file or directory
sysctl: cannot stat /proc/sys/net/ipv4/icmpignoreboguserrorrespons­es: No such file or directory